### Describe the issue you are experiencing
Related to #4210
I still encounte…r the same TimeoutError even after using the newest version 2.15.3.
Would be great if someone could point me in the right direction.
I'm using a SMLight SLZB-MR3U with Zigbee and Thread activated. Thread runs on the EFR32MG24 chip with flow control "off" and Serial Speed of 460800.
I also tried it with flow control "on" on both sides.
Firmware on the SMLight SLZB-MR3U:
```
SLZB-OS v3.1.4
Firmware type: Matter-over-Thread
Revision: 20250212
```
Addon config:
```
device: /dev/ttyS1
baudrate: "460800"
flow_control: false
otbr_log_level: notice
firewall: false
nat64: false
network_device: 10.0.86.192:6638
```
Log:
```
[17:28:47] INFO: The otbr-web is disabled.
[17:28:47] INFO: Enabled socat-otbr-tcp.
s6-rc: info: service socat-otbr-tcp: starting
s6-rc: info: service mdns: starting
s6-rc: info: service s6rc-oneshot-runner: starting
s6-rc: info: service mdns successfully started
s6-rc: info: service s6rc-oneshot-runner successfully started
s6-rc: info: service fix-attrs: starting
s6-rc: info: service banner: starting
s6-rc: info: service fix-attrs successfully started
s6-rc: info: service legacy-cont-init: starting
s6-rc: info: service legacy-cont-init successfully started
[17:28:47] INFO: Starting mDNS Responder...
Default: mDNSResponder (Engineering Build) (Dec 15 2025 09:14:53) starting
[17:28:47] INFO: Starting socat TCP client for OTBR daemon...
-----------------------------------------------------------
Add-on: OpenThread Border Router
OpenThread Border Router add-on
-----------------------------------------------------------
Add-on version: 2.15.3
You are running the latest version of this add-on.
s6-rc: info: service socat-otbr-tcp successfully started
System: Home Assistant OS 16.3 (amd64 / qemux86-64)
Home Assistant Core: 2025.12.3
Home Assistant Supervisor: 2025.12.3
-----------------------------------------------------------
Please, share the above information when looking for help
or support in, e.g., GitHub, forums or the Discord chat.
-----------------------------------------------------------
s6-rc: info: service banner successfully started
s6-rc: info: service otbr-agent: starting
[17:28:48] INFO: Migrating OTBR settings if needed...
2025-12-15 17:28:48 homeassistant asyncio[237] DEBUG Using selector: EpollSelector
2025-12-15 17:28:48 homeassistant zigpy.serial[237] DEBUG Opening a serial connection to '/tmp/ttyOTBR' (baudrate=460800, xonxoff=False, rtscts=False)
2025-12-15 17:28:48 homeassistant serialx.platforms.serial_posix[237] DEBUG Configuring serial port '/tmp/ttyOTBR'
2025-12-15 17:28:48 homeassistant serialx.platforms.serial_posix[237] DEBUG Configuring serial port: [0, 0, 3248, 0, 4100, 4100, [b'\x03', b'\x1c', b'\x7f', b'\x15', b'\x04', 0, 0, b'\x00', b'\x11', b'\x13', b'\x1a', b'\x00', b'\x12', b'\x0f', b'\x17', b'\x16', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00']]
2025-12-15 17:28:48 homeassistant serialx.platforms.serial_posix[237] DEBUG Setting low latency mode: True
2025-12-15 17:28:48 homeassistant serialx.platforms.serial_posix[237] DEBUG Device is not a serial port, cannot set low latency
2025-12-15 17:28:48 homeassistant serialx.platforms.serial_posix[237] DEBUG Setting modem pins: ModemPins[!dtr !rts]
2025-12-15 17:28:48 homeassistant serialx.platforms.serial_posix[237] DEBUG TIOCMBIC: 0x00000006
2025-12-15 17:28:48 homeassistant serialx.platforms.serial_posix[237] DEBUG Device is not a serial port, cannot set modem pins
2025-12-15 17:28:48 homeassistant zigpy.serial[237] DEBUG Connection made: <serialx.platforms.serial_posix.PosixSerialTransport object at 0x7f0de07bf810>
2025-12-15 17:28:48 homeassistant universal_silabs_flasher.spinel[237] DEBUG Sending frame SpinelFrame(header=SpinelHeader(transaction_id=0, network_link_id=0, flag=2), command_id=<CommandID.RESET: 1>, data=b'\x02')
2025-12-15 17:28:48 homeassistant universal_silabs_flasher.spinel[237] DEBUG Sending data b'~\x80\x01\x02\xea\xf0~'
2025-12-15 17:28:48 homeassistant serialx.descriptor_transport[237] DEBUG Immediately writing b'~\x80\x01\x02\xea\xf0~'
2025-12-15 17:28:48 homeassistant serialx.descriptor_transport[237] DEBUG Sent 7 of 7 bytes
2025-12-15 17:28:50 homeassistant universal_silabs_flasher.spinel[237] DEBUG Device did not respond to reset, continuing
2025-12-15 17:28:50 homeassistant universal_silabs_flasher.spinel[237] DEBUG Sending frame SpinelFrame(header=SpinelHeader(transaction_id=3, network_link_id=0, flag=2), command_id=<CommandID.PROP_VALUE_GET: 2>, data=b'\x08')
2025-12-15 17:28:50 homeassistant universal_silabs_flasher.spinel[237] DEBUG Sending data b'~\x83\x02\x08\xbc\x9a~'
2025-12-15 17:28:50 homeassistant serialx.descriptor_transport[237] DEBUG Immediately writing b'~\x83\x02\x08\xbc\x9a~'
2025-12-15 17:28:50 homeassistant serialx.descriptor_transport[237] DEBUG Sent 7 of 7 bytes
2025-12-15 17:28:52 homeassistant universal_silabs_flasher.spinel[237] DEBUG Failed to send SpinelFrame(header=SpinelHeader(network_link_id=0, flag=2), command_id=<CommandID.PROP_VALUE_GET: 2>, data=b'\x08'), trying again in 0.10s (attempt 1 of 3)
2025-12-15 17:28:52 homeassistant universal_silabs_flasher.spinel[237] DEBUG Sending frame SpinelFrame(header=SpinelHeader(transaction_id=3, network_link_id=0, flag=2), command_id=<CommandID.PROP_VALUE_GET: 2>, data=b'\x08')
2025-12-15 17:28:52 homeassistant universal_silabs_flasher.spinel[237] DEBUG Sending data b'~\x83\x02\x08\xbc\x9a~'
2025-12-15 17:28:52 homeassistant serialx.descriptor_transport[237] DEBUG Immediately writing b'~\x83\x02\x08\xbc\x9a~'
2025-12-15 17:28:52 homeassistant serialx.descriptor_transport[237] DEBUG Sent 7 of 7 bytes
2025-12-15 17:28:54 homeassistant universal_silabs_flasher.spinel[237] DEBUG Failed to send SpinelFrame(header=SpinelHeader(network_link_id=0, flag=2), command_id=<CommandID.PROP_VALUE_GET: 2>, data=b'\x08'), trying again in 0.10s (attempt 2 of 3)
2025-12-15 17:28:54 homeassistant universal_silabs_flasher.spinel[237] DEBUG Sending frame SpinelFrame(header=SpinelHeader(transaction_id=3, network_link_id=0, flag=2), command_id=<CommandID.PROP_VALUE_GET: 2>, data=b'\x08')
2025-12-15 17:28:54 homeassistant universal_silabs_flasher.spinel[237] DEBUG Sending data b'~\x83\x02\x08\xbc\x9a~'
2025-12-15 17:28:54 homeassistant serialx.descriptor_transport[237] DEBUG Immediately writing b'~\x83\x02\x08\xbc\x9a~'
2025-12-15 17:28:54 homeassistant serialx.descriptor_transport[237] DEBUG Sent 7 of 7 bytes
2025-12-15 17:28:56 homeassistant universal_silabs_flasher.spinel[237] DEBUG Failed to send SpinelFrame(header=SpinelHeader(network_link_id=0, flag=2), command_id=<CommandID.PROP_VALUE_GET: 2>, data=b'\x08'), trying again in 0.10s (attempt 3 of 3)
2025-12-15 17:28:56 homeassistant serialx.descriptor_transport[237] DEBUG Closing at the request of the application
2025-12-15 17:28:56 homeassistant zigpy.serial[237] DEBUG Waiting for serial port to close
2025-12-15 17:28:56 homeassistant serialx.descriptor_transport[237] DEBUG Closing connection: None
2025-12-15 17:28:56 homeassistant serialx.descriptor_transport[237] DEBUG Closing file descriptor 7
2025-12-15 17:28:56 homeassistant serialx.descriptor_transport[237] DEBUG Calling protocol `connection_lost` with exc=None
2025-12-15 17:28:56 homeassistant zigpy.serial[237] DEBUG Connection lost: None
Traceback (most recent call last):
File "/usr/local/lib/python3.11/dist-packages/universal_silabs_flasher/spinel.py", line 260, in send_frame
return await asyncio.shield(future)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
asyncio.exceptions.CancelledError
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/local/bin/migrate_otbr_settings.py", line 223, in <module>
asyncio.run(main())
File "/usr/lib/python3.11/asyncio/runners.py", line 190, in run
return runner.run(main)
^^^^^^^^^^^^^^^^
File "/usr/lib/python3.11/asyncio/runners.py", line 118, in run
return self._loop.run_until_complete(task)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.11/asyncio/base_events.py", line 653, in run_until_complete
return future.result()
^^^^^^^^^^^^^^^
File "/usr/local/bin/migrate_otbr_settings.py", line 154, in main
hwaddr = await get_adapter_hardware_addr(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/bin/migrate_otbr_settings.py", line 101, in get_adapter_hardware_addr
rsp = await protocol.send_command(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/dist-packages/universal_silabs_flasher/spinel.py", line 292, in send_command
return await self.send_frame(frame, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/dist-packages/universal_silabs_flasher/spinel.py", line 259, in send_frame
async with asyncio_timeout(timeout):
File "/usr/lib/python3.11/asyncio/timeouts.py", line 98, in __aexit__
raise TimeoutError
TimeoutError
[17:28:56] WARNING: otbr-agent exited with code 1 (by signal 0).
otbr-ingress-deny-src
otbr-ingress-deny-src-swap
otbr-ingress-allow-dst
otbr-ingress-allow-dst-swap
[17:28:57] INFO: OTBR firewall teardown completed.
s6-svlisten1: fatal: /run/s6-rc/servicedirs/otbr-agent failed permanently or its supervisor died
s6-rc: warning: unable to start service otbr-agent: command exited 1
s6-rc: info: service legacy-cont-init: stopping
s6-rc: info: service banner: stopping
s6-rc: info: service socat-otbr-tcp: stopping
s6-rc: info: service mdns: stopping
/run/s6/basedir/scripts/rc.init: warning: s6-rc failed to properly bring all the services up! Check your logs (in /run/uncaught-logs/current if you have in-container logging) for more information.
/run/s6/basedir/scripts/rc.init: fatal: stopping the container.
Default: mDNSResponder (Engineering Build) (Dec 15 2025 09:14:53) stopping
2025/12/15 17:28:57 socat[78] W exiting on signal 15
s6-rc: info: service banner successfully stopped
s6-rc: info: service socat-otbr-tcp successfully stopped
s6-rc: info: service legacy-cont-init successfully stopped
s6-rc: info: service fix-attrs: stopping
s6-rc: info: service fix-attrs successfully stopped
s6-rc: info: service s6rc-oneshot-runner: stopping
s6-rc: info: service s6rc-oneshot-runner successfully stopped
[17:28:57] INFO: mDNS ended with exit code 4 (signal 0)...
s6-rc: info: service mdns successfully stopped
```
### What type of installation are you running?
Home Assistant OS
### Which operating system are you running on?
Home Assistant Operating System
### Which add-on are you reporting an issue with?
OpenThread Border Router
### What is the version of the add-on?
2.15.3
### Steps to reproduce the issue
Use the setup as described above and try to start the addon.
### System Health information
## System Information
version | core-2025.12.3
-- | --
installation_type | Home Assistant OS
dev | false
hassio | true
docker | true
container_arch | amd64
user | root
virtualenv | false
python_version | 3.13.9
os_name | Linux
os_version | 6.12.51-haos
arch | x86_64
timezone | Europe/Zurich
config_dir | /config
<details><summary>Home Assistant Community Store</summary>
GitHub API | ok
-- | --
GitHub Content | ok
GitHub Web | ok
HACS Data | ok
GitHub API Calls Remaining | 5000
Installed Version | 2.0.5
Stage | running
Available Repositories | 2492
Downloaded Repositories | 2
</details>
<details><summary>Home Assistant Cloud</summary>
logged_in | false
-- | --
can_reach_cert_server | ok
can_reach_cloud_auth | ok
can_reach_cloud | ok
</details>
<details><summary>Home Assistant Supervisor</summary>
host_os | Home Assistant OS 16.3
-- | --
update_channel | stable
supervisor_version | supervisor-2025.12.3
agent_version | 1.7.2
docker_version | 28.3.3
disk_total | 30.8 GB
disk_used | 14.4 GB
nameservers | 10.0.86.14, 10.0.86.25, 10.0.86.24
healthy | true
supported | true
host_connectivity | true
supervisor_connectivity | true
ntp_synchronized | true
virtualization | kvm
board | ova
supervisor_api | ok
version_api | ok
installed_addons | Studio Code Server (6.0.1), ESPHome Device Builder (2025.11.5), Mosquitto broker (6.5.2), Zigbee2MQTT (2.7.1-1), Advanced SSH & Web Terminal (22.0.3), OpenThread Border Router (2.15.3)
</details>
<details><summary>Dashboards</summary>
dashboards | 2
-- | --
resources | 1
views | 2
mode | storage
</details>
<details><summary>Network Configuration</summary>
adapters | lo (disabled), enp6s18 (enabled, default, auto), hassio (disabled), docker0 (disabled), veth1fd53b6 (disabled), vetha2fdbe1 (disabled), vethfd5ce4d (disabled), veth6552bc0 (disabled), veth52d2477 (disabled), vethb722268 (disabled), veth3f01e4a (disabled), veth9060106 (disabled), vethfe0d781 (disabled)
-- | --
ipv4_addresses | lo (127.0.0.1/8), enp6s18 (10.0.86.27/24), hassio (172.30.32.1/23), docker0 (172.30.232.1/23), veth1fd53b6 (), vetha2fdbe1 (), vethfd5ce4d (), veth6552bc0 (), veth52d2477 (), vethb722268 (), veth3f01e4a (), veth9060106 (), vethfe0d781 ()
ipv6_addresses | lo (::1/128), enp6s18 (fe80::8c2f:f146:87a5:d4af/64), hassio (fd0c:ac1e:2100::1/48, fe80::f4e3:f9ff:fead:13e1/64), docker0 (fe80::bcca:33ff:fe05:1dde/64), veth1fd53b6 (fe80::d043:18ff:fefb:47cb/64), vetha2fdbe1 (fe80::63:22ff:fe85:c20c/64), vethfd5ce4d (fe80::1cdf:44ff:fedb:dd0a/64), veth6552bc0 (fe80::8c41:19ff:feb1:ad84/64), veth52d2477 (fe80::832:21ff:fead:1294/64), vethb722268 (fe80::dc55:4fff:feff:9028/64), veth3f01e4a (fe80::2891:a0ff:fede:cbe2/64), veth9060106 (fe80::7088:3aff:fe07:8c37/64), vethfe0d781 (fe80::f883:53ff:fe4c:36f2/64)
announce_addresses | 10.0.86.27, fe80::8c2f:f146:87a5:d4af
</details>
<details><summary>Recorder</summary>
oldest_recorder_run | 4 December 2025 at 15:06
-- | --
current_recorder_run | 13 December 2025 at 13:59
estimated_db_size | 223.43 MiB
database_engine | sqlite
database_version | 3.49.2
</details>
### Anything in the Supervisor logs that might be useful for us?
```txt
```
### Anything in the add-on logs that might be useful for us?
```txt
```
### Additional information
_No response_